Cisco CCNA Routing and Switching ICND2 200-101 Official Cert Guide

IOS Images per Model, Series, and per Software Version/Release

Since the early days of Cisco, back in the 1980s, through about the first 10 years of this century, Cisco created each IOS image for a particular router model, version and release, and feature set.

First, Cisco needed different IOS images for different router models, or at least for different router families, because of hardware differences. A low-end router with limited physical interfaces needed different software to support its interfaces than a high-end router that supported many different types of interface cards. Also, different router models often used different processors, so Cisco compiled different IOS images for use on those different processors.

Second, Cisco needed different ...